Future sub sea installations will require equipment for increasing the pressure in the well flow in order to achieve optimum exploitation of the reservoir. Use of machines which increases the pressure, contribute to a reduction of the down hole pressure in the well. This will then lead to an accelerating production from the reservoir, providing a possibility for maintaining a stable flow regime through the well casing, so that formation of fluid plugs is avoided. Prior art solutions comprise use of pumps for pumping liquids (water and raw oil, etc.), and mixing of liquid and gas where the liquid represents more than 5 volume %, while compressors which are able to pump wet gas, are under development and testing. Today, compressors have limited capacity, and the increase in pressure and power are at maximum limited to a few megawatts. Hence, there is a need for development of compressor systems which may handle large volumes of gas having in part substantial pressure differences and with power up to several tens of megawatts.
The challenges to be met in this respect are amongst others transfer of large effect volumes below sea level; handling of sand, water, oil/condensate, and gas; together with possible pollution, such as production chemicals, hydrate inhibitors, pollutions from the reservoir; and uneven distribution of such matter over the life span of the field; liquid plugs during the start-up phase and transients, etc.
Solutions exit for such systems. All the systems have a common denominator, namely their dependence of the functioning of a number of components, having to work together in order to obtain the required system functionality. Many of these prior art components are not qualified for use in connection with offshore exploitation of oil.
GB 2 264 147 discloses a booster arrangement for boosting multi-phase fluids from a reservoir in a formation to a processing plant, where the boosting arrangement is placed in a flow line between the reservoir and the processing plant. The arrangement comprises a separation vessel for separation of liquid/gas, where said separation vessel has an inlet for supplying a mixture of oil and gas prior to further separate transport of the gas and the liquid. Further, the boosting arrangement comprises a motor driven pump, designed to lift the liquid fraction out of the scrubber and further to a jet pump, while the separated gas is allowed to flow through a separate pipe to said jet pump. From the jet pump, the mixed gas and liquid is then compressed to a processing plant at a substantially higher pressure than the pressure at the inlet to the separation vessel.